Browsing by Author "Omwenea, Philip Isaac"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Bio-based succinic acid recovery by ion exchange resins integrated with nanofiltration/reverse osmosis preceded crystallization
    (Elsevier, 2021-07-03) Omwenea, Philip Isaac; Sarihan, Zehra Betul Ocal; Karagunduz, Ahmet; Keskinlera, Bulen
    Succinic acid is a key platform chemical for production of various products such as biodegradable polymers, pharmaceuticals, fine chemicals and foods. In the present study, bio-based succinic acid was recovered through two processes. Process I consisted of chromatographic separation with anionic exchange resin followed by direct crystallization, whereas process II sequentially consisted of cationic exchanger, activated carbon, NF/RO membrane, vacuum distillation, and crystallization. The highest chromatographic separation efficiency for succinic acid by Amberlite IRA900 Cl column was calculated as 69.3% at flow rate of 0.42 BV/h. Rejection of succinic aid (SA), lactic acid (LA), formic acid (FA) and acetic acid (AC) by NF90 membrane was 53.1, 51.8, 46.6 and 39.8%, respectively at pH less than 2. However, at pH 6.8 the respective rejections increased to 96.8, 90.6, 71.3 and 70.5%. Double pass with BW30 or HP reverse osmosis membranes achieved retention of SA, LA, FA and AC of 95.9%, 95.8%, 65.4% and 46.9%, respectively. Analysis of generated SA crystals by X-ray diffraction technique (XRD) and Fourier transform infrared (FTIR) showed the crystallinity of recovered SA as conformable to standard grade crytsals. The purity of generated succinic acid crystals was recorded as 98.5% and 96.7% for process I and process II, respectively. The calculated succinic acid yield was 78% for process I and 65% for process II. Herein, we demonstrated two alternative systems for bio-based succinic acid recovery, which will set a stage for research in efficient downstream purification of SA.
  • Thumbnail Image
    Item
    Phosphorous removal from anaerobically digested municipal sludge centrate by an electrocoagulation reactor using metal (Al, Fe and Al-Fe) scrap anodes.
    (Elsevier, 2021-06-02) Kobya, Mehmet; Omwenea, Philip Isaac; Sarabia, Sanaz Mohammadzadeh; Yildirim, Sadullah; Ukundimana, Zubeda
    Phosphates are a major cause of eutrophication and growth of algal blooms in surface waters. The current study investigated phosphorus removal from sludge centrate effluent (SCE) of a municipal wastewater plant by packed-bed electrocoagulation (EC) reactor. Distinctively, iron (Fe), aluminum (Al) and Al-Fe hybrid scrap anodes were used. The influence of initial pHi, applied current and packed anode bed density were evaluated. Phosphorous removal efficiency of 99.99 % was obtained at applied current of 0.20A with anode bed densities of 0.18 kg Al/m3 (pHi 5.0) and 0.48 kg Fe/m3(pHi 7.0). Optimum operating costs entailing sludge disposal, chemical, energy and electrode consumption were calculated as 0.379 US $/m3 (6.04 $/kg PO4-P) for Fe scrap, 0.494 US $/m3 (9.46 $/kg PO4-P) for Al scrap and 0.501 US $/m3 (9.59 $/kg PO4-P) for Al-Fe hybrid scraps. Phosphorus removal per electrochemically generated metal was 191.22 mg P/g Al, 104.88 mg P/g Fe, and 61.08 mg P/g (Al + Fe). The molar metal to phosphorus ratio at optimum conditions were calculated as 5.41, 3.97 and 7.65 mol/mole for Al, Fe and Al-Fe, respectively. The key mechanisms for phosphorus removal were metal-phosphorus precipitation and adsorption. Herein, metal scrap anodes have been proved effective for phosphorous removal from SCE.
  • Thumbnail Image
    Item
    Recovery of succinic acid from whey fermentation broth by reactive extraction coupled with multistage processes
    (Science Direct, 2020-06) Omwenea, Philip Isaac; Yagcioglu, Meltem; Sarihan, Zehra Betül Ocal; Karagunduz, Ahmet; Keskinler, Bülent
    Fermentative production of succinic acid (SA) from renewable resources such as whey is environmentally sustainable compared to petroleum-based synthesis. However, a major drawback of fermentation is the concurrent production of SA with byproducts such as lactic acid (LA), formic acid (FA) and acetic acid (AA). Therefore, appropriate downstream SA recovery and purification steps are significant in ensuring sustainable SA production. In this study, SA was fermented by Actinobacillus succinogenes and recovered in an integrated process consisting of ultrafiltration, vacuum distillation and reactive extraction. The extractant used was tri-n-octylamine (TOA) with 1-octanol as a diluent for both liquid-liquid (LLE) extraction and supported liquid membrane (SLM). The produced SA titer and yield was 11.16 g/L and 0.44 g/g, respectively. The steady state ultrafiltration permeate flux ranged from 31.18 to 33.42 L/m2h, and complete decolorization of the fermentation broth was achieved with 10 % (w/v) of powdered activated carbon. The extraction efficiency for LLE was 51.5 %, whereas SLM achieved 57.3 % recovery. SA exhibited transport and permeability coefficient of 0.00697 h−1 (R2 > 0.92) and 0.08605 cm h−1, respectively. Extraction of SA tremendously decreased as the aqueous pH was increased from 2 to 5. In SLM, initial SA flux was calculated as 9.65 g/m2h and doubled that of lactic acid. Selective extraction of only SA was not achieved; however, residue biological material and macromolecular substances were effectively removed. Herein, we clearly demonstrated that process integration applied in reactive extraction is a promising approach for recovery of SA from fermentation broth.